The present invention relates to drive sprockets used in driving a sawchain of a chain saw.
Chain saws are used for felling trees and cutting timber to a desired length. Chain saws can be hand-held, vehicle mounted or stationary. The power of the motor is converted to a cutting force in the chain through a drive sprocket, and to facilitate the use of a small high speed motor it is desirable to use a sprocket with small diameter.
Many problems in using a chain saw involve the cooperation between the drive sprocket and the chain. A sprocket with few teeth may cause uneven motion, vibrations and sudden stresses in the chain. This will deform and stretch the chain, which then does not fit the sprocket well enough, causing even worse vibrations and ultimately a risk of chain breakage.
Since sawing normally is performed with the part of the chain which moves towards the drive sprocket, this will operate in an environment of sawdust, fibers and resin.